According to some, the third sector is unsuited to singular definitions because it is by its nature unruly. However, different definitions or theorizations can be identified. Ontologically oriented definitions of the third sector offer differing views on what it is made up of and what is excluded. Thus, an American view defines it as a separate sector characterized by organized, private, nonprofit, and voluntary entities. A European definition sees it as a hybrid phenomenon combining and connecting other sectors such as state and market (this allows social enterprises and [welfare] state bodies in). In contrast, epistemologically oriented theorizations treat the third sector more as a process or form of practice: a particular type of communication (following systems theory), a form of ordering and governing of people (following discourse theory), or a form of struggle or dialogue between social forces (following critical theory).